The right answer is A in my view.Split #1: who vs whom.
The verbs had listened/listens/was listening require a subject pronoun rather than an object pronoun. Hence the subject pronoun
who rather than
whom is appropriate in the context. Based on this split, we can eliminate B and C for the wrongful use of the object pronoun whom.
Split #2: had listened vs was listening.
In order to determine which of the two tenses is correct, we need to look at the meaning of the sentence. There was an event and clearly the event was over and the audience
had filed out per the information provided in the non-underlined portion. After the show ended, Serge began to wonder about who
had listened/listens/was listening to his long speech. It is worth noting that the action of listening took place in the past. So, the simple present tense
listens is incorrect. In addition, the act of listening was not a background activity before Serge began to ponder because the show had ended and the audience had filed out before he began to wonder. Hence,
was listening is incorrect. The act of listening is a past prior action hence the right verb tense is
had listened. Based on this, D and E can be eliminated for the use of the wrong verb tense.
We are left with A as the best answer that conveyed the sequence of events using the right verb-tense
had listened and also the subject pronoun
who.
Once the audience had filed out, Serge began to wonder who, if anyone, had listened to his long speech.
A. began to wonder
who, if anyone,
had listened to his long speech.
B. began wondering
whom, if anyone,
had listened to his long speech.
C. began wondering
whom, if anyone,
listens to his long speech.
D. began to wonder
who, if anyone,
was listening to his long speech.
E. began wondering
who, if anyone,
was listening to his long speech.